The invention herein resides in the art of brake control systems for aircraft and is particularly related to those systems incorporating automatic deceleration control or automatic braking functions. It will be appreciated herein that the instant invention, while being discussed with respect to aircraft, is applicable to any braked wheel vehicle. Similarly, it will be readily appreciated by those skilled in the art that the instant invention may be incorporated into brake control systems which utilize state-of-the-art antiskid systems, in which case the instant invention will be utilized for metering the appropriate brake pressure in lieu of manual operation of the main brake pressure control valve. In the hydraulic system of an aircraft utilizing the invention, a shuttle valve would be interposed between the manually controlled brake pedals of the pilot and the control circuit described herein. That source demanding the greater braking effort will control, via the shuttle valve. Of course, antiskid circuitry may still be included with each of the braked wheels.
For a general understanding of certain of the benefits of automatic braking systems, reference may be had to U.S. Pat. No. 3,829,167, to the applicant herein and Harold R. Booher. In the system of that patent, the actual rate of deceleration hunts about a desired rate of deceleration as evidenced by the control signals shown in FIG. 3 thereof. While the patented system has proven to be a very satisfactory one, this hunting technique has been found to be less desirable than a system in which the actual deceleration rate seldom overshoots the desired rate. By alleviating the hunting technique, it has been found that the braking effort is more efficient and more conducive to passenger comfort.